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#include <stdio.h>
#include <stdlib.h>
#include <string.h>
void *errorchecked_malloc(unsigned int);
int main(int argc, const char *argv[])
{
char *char_ptr;
int *int_ptr;
int mem_size;
if (argc < 2)
mem_size = 50;
else
mem_size = atoi(argv[1]);
printf("\t[+] allocating %d bytes of memory on the heap for char_ptr\n", mem_size);
char_ptr = (char *) errorchecked_malloc(mem_size);
strcpy(char_ptr, "this memory is located on the heap.");
printf("char_ptr (%p) --> '%s'\n", char_ptr, char_ptr);
printf("\t[+] allocating 12 bytes of memory on the heap for int_ptr\n");
int_ptr = (int *) errorchecked_malloc(12);
*int_ptr = 31337;
printf("int_ptr (%p) --> %d\n", int_ptr, *int_ptr);
printf("\t[-] freeing char_ptr's heap memory...\n");
free(char_ptr);
printf("\t[+] allocating another 15 bytes for char_ptr\n");
char_ptr = (char *)errorchecked_malloc(15);
strcpy(char_ptr, "new memory");
printf("char_ptr (%p) --> '%s'\n", char_ptr, char_ptr);
printf("\t[-] freeing int_ptr's heap memory...\n");
free(int_ptr);
printf("\t[-] freeing char_ptr's heap memory...\n");
free(char_ptr);
return 0;
}
void *errorchecked_malloc(unsigned int size)
{
void *ptr;
ptr = malloc(size);
if (ptr == NULL) {
fprintf(stderr, "Error: could not allocate heap memory.\n");
exit(-1);
}
return ptr;
}
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